“We are concerned that Google did not disclose until long after the fact that consumers’ Internet use was being recorded, analyzed and perhaps profiled," wrote Reps. Joe Barton (R-Texas), Edward Markey (D-Mass.) and Henry Waxman (D-Beverly Hills). "In addition, we are concerned about the completeness and accuracy of Google’s public explanations about this matter."

On Tuesday, Google confirmed to The Times that before regulators' questioning, the company had never disclosed its Wi-Fi collection practices directly to its users. The company pointed out that the practice was not secret -- it had been documented in a Wikipedia article and elsewhere -- but Google had not itself told users that its cars were recording Wi-Fi information.

The lawmakers sent Schmidt a dozen questions asking for clarification on the scope and depth of the information collected by Street View vehicles, including whether Google has "analyzed and used" the data in any way, or had plans to in the future.

The letter also asked if Google had ever conducted a legal analysis about whether consumer privacy laws applied to its collection of more than 600 gigabytes of Wi-Fi data.

Google began to explain its Wi-Fi collection in late April after European regulators began asking the company what kinds of data its mapping cars were collecting. At first, Google said it did not collect so-called "payload data" -- the actual content of users that could include e-mails and personal information. But then Google did an about-face, saying it had indeed been collecting snippets of private data because of an oversight in the way its software was written.

Because of this revelation, regulators in several countries have begun inquiries into why and how Google could have amassed a trove of private data without the awareness or consent of its users.

Leibowitz has told a Senate committee that the FTC would "take a very, very close look at this," and that it was "one example of why consumers have very serious privacy concerns about data that's being collected."